There are instances where it is desirable to have a sterile access to the brain for conducting a diagnostic or therapeutic procedure in a non-sterile environment. For example, techniques have been developed to position medical devices in the brain using an externally applied magnetic field. These techniques are most conveniently employed in a non-sterile environment where the equipment is available for generating the appropriate magnetic field. Similarly, it is often desirable to monitor a procedure with x-ray or magnetic resonance imaging equipment that is available only in non-sterile environments. There are also situations where repeated access to the brain is needed to complete a diagnostic or therapeutic procedure, but it is undesirable to perform repeated surgeries each time access is required.
It is also desirable to be able to releasably anchor medical devices inserted in to the body to prevent unintentional movement during a medical procedure, or to allow a medical device to remain in place between medical procedures, rather than reinserting the medical device at the start of each procedure.